The purpose of this proposed study is to develop, pilot and validate a set of theoretically and empirically implicated measures of neighborhood social processes that may be important in understanding risk and protection for youth violence. Building from a developmental-ecological model (Bronfenbrenner,1987;Tolan, Guerra and Kendall, 1995) and the theoretical and empirical literature on community and neighborhood influences on youth development and violence (Leventhal &Brooks-Gunn, 2000;Sampson et al., 1997), measures will be developed, refined and tested that capture characteristics of neighborhoods that are likely to have direct effects on risk for youth violence, but also indirect effects through or in interaction with other important socializing systems such as family, peer and schools. We will use these measures to empirically test the extent to which these factors are associated with youth risk and protection for violence perpetration and victimization. The proposed study has five specific aims: 1) to develop and refine measures and methods of measurement of important social processes (norms, social support and connection, social control, and routine activities) that theory and prior research indicate are related to risk and protection of youth violence;2) to validate these neighborhood level measures through evaluation of the relation of these characteristics to neighborhood level of youth violence and school performance;3) to test the specific contribution of each construct as measured by the neighborhood informant sample to individual risk for violence victimization and perpetration and to evaluate neighborhood as moderator of family risk on child aggression and violence, school functioning, and other indicators of child social functioning;4) to test the variation in explanatory role of each construct to risk at two distinct developmental stages - adolescence and school entry;and 5) to test the relation between community structural characteristics (e.g., poverty, mobility, economic viability) and neighborhood social processes and how variation in that relation explains youth risk for violence and family functioning and other theorized moderators of neighborhood risk for individuals. To test these aims, we plan to select 30 urban neighborhoods within Chicago. Neighborhoods will be selected to have a majority of either African American or Latino residents. Within these neighborhoods, we propose to collect data from two separate samples: 1) adolescents and adults as neighborhood informants to measure "neighborhood level" constructs with theoretical and empirical links to risk for youth violence, and 2) a separate sample of children, adolescents and their caregivers to test the extent to which neighborhood factors are associated with youth risk for violence perpetration and victimization. We include two age groups within this second sample, families with young children (ages 5-6 as they are entering school) and families with adolescents (14-18) to evaluate the developmental impact of these processes. A better understanding of these mechanisms is critical for improving existing prevention programs and for developing new interventions. PUBLIC HEALTH RELEVANCE: This study will provide important knowledge related to the measurement of neighborhood social processes thought to be important in understanding risk and protection for youth violence. Despite the tremendous growth in number of studies focused on neighborhood, there remains relatively limited understanding of how they matter or the processes through which neighborhoods relate to risk and protection. By developing psychometrically sound and valid measures of these neighborhood social processes, and by testing the relations between these constructs and outcomes such as youth violence, delinquency, and substance use, the proposed research will improve our understanding of the developmental processes influenced by neighborhood characteristics and contribute to the development of more effective interventions for the prevention of youth violence.